Dentists have found it useful to have a cast or replica of a patient's anatomy when analyzing and treating disorders of the jaws and making a dental prostheses. A dentist or prosthodontist will generally need a cast of an area of a patient's mouth where one or more teeth are missing and need replacement. This cast can be used in the dental lab to adjust and fit replacement teeth for proper size and shape, eliminating the need for the patient to be present. To create casts, an impression of the patient's upper and lower dental arch is first obtained. The impression is made by placing a curable material in an impression tray and positioning the tray over the patient's teeth and gums. After the material has cured it and the tray are removed from the mouth. The same process is used for both the upper and lower jaw. The actual dental cast is then made by pouring or placing a second curable material in the cured impression material. After the second material has cured the impression material is removed to produce the dental cast. Properly made, these dental casts provide an accurate physical replica of the patient's upper and lower teeth as well as the adjacent soft tissue. Modern impression materials can create casts that reproduce detail as fine as 10 microns.
A face bow may also be used to measure the distance and angulation of the upper arch in relation to the patient's temporal mandibular joint (TMJ). When used, the upper cast is mounted with the face bow in a device called an articulator such that the rotations centers approximate those of the patient. Other types of face bows record the position of the teeth in relation to the patient's “natural head position” or anatomic landmarks such as the ala of the nose and the tragus of the ear. Finally, many aesthetic aspects of the face may need to be mechanically recorded to have the proper information needed to plan aesthetic and functional dental prosthetics.
Casts are generally mounted in an articulator to reproduce the spatial relationship of the upper jaw to the lower and to approximate the movement of the patient's jaws. Frequently a specific jaw relationship is recorded in a wax bite. Wax is placed in the patient's mouth and the teeth are closed into the wax to record indentations of the teeth and to record the relative position of the upper and lower dental arch. Dental casts can then be placed into the wax bite and joined to the articulator such that the bite position can be reproduced by the articulator in the dental laboratory. The casts of a patient's teeth can also be mounted in an articulator by indexing the teeth in one arch into the teeth of the other in a position called maximum intercuspation. This eliminates the need for a wax bite. Many materials can be used instead of wax to make the bite record and many jaw positions may be recorded for specific dental applications.
Dental radiographs are also important in the diagnosis of aesthetic and functional dental problems. Orthodontists and oral surgeons use a lateral head film called a cephalometric radiograph to determine the length of the upper and lower jaws, the angulation of the teeth and the contour of the soft tissues. Many measurements can be made on these films to determine how the patient's anatomy is different from normal findings. Medical computed tomography (CT) has also been used extensively for evaluation of trauma and to plan for the placement of dental implants. CT has the advantage that the images are isometric and not distorted so that precise measurement of the bone and teeth can be made. New cone beam CT units are less expensive than conventional medical CT, have much lower radiation, are faster and allow the patient to be sitting upright in the “natural head position” for imaging. Unfortunately, dental radiographs and CT may produce scatter from metal fillings, gold crowns and other dental devices. This scatter may make the three-dimensional images of the teeth and occlusal surfaces of the teeth very imprecise and not of diagnostic quality. Even data from a patient without metal restorations may be not accurate enough for occlusal analysis when using CT as the only imaging process.
In recent years many patients not only want to have a healthy mouth and teeth but also want to improve their appearance with teeth that are in harmony with their face, lips, hair and eyes. Thus, it is desirable that a simplified system be developed to eliminate the need for a face bow and dental articulator. It would also be beneficial to create a precise virtual model of the patient's teeth and soft and hard tissues without scatter and at a lever of precision in the 10-20 micron range for occlusal analysis.
The devices, systems, and methods of the present disclosure overcomes one or more problems disclosed herein or in the art.